Easily dyeable spandex and method of making same
By introducing polyether ester polyols into the molecular structure of spandex, its hydrophilicity and dye interaction are enhanced, solving the problem of poor dyeing effect of spandex fibers and realizing the preparation of spandex fibers with high dyeing rate and color fixation rate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHENGZHOU ZHONGYUAN SPANDEX ENG TECH CO LTD
- Filing Date
- 2024-04-16
- Publication Date
- 2026-06-30
AI Technical Summary
Existing spandex fibers have poor dyeing rate and color fastness during the dyeing process, especially when blended with other fibers, they are prone to color difference or "white showing" phenomenon, which affects the appearance of textile products.
By introducing polyether ester polyols with specific structures into the spandex molecular structure, the hydrophilicity of the molecular chain and the interaction force between dye molecules and spandex are increased. Easily dyeable spandex is prepared by dry spinning or melt spinning methods, thereby improving its dyeing rate and color-fixing ability for disperse dyes and acid dyes.
Without compromising the mechanical properties of spandex, the dyeing rate and fixation ability of spandex fibers for disperse and acid dyes were significantly improved, thus enhancing the dyeing effect.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical fibers, specifically to an easily dyeable spandex and a method for preparing easily dyeable spandex. Background Technology
[0002] Spandex, or polyurethane fiber, is currently the most widely used elastic fiber. In application, spandex is rarely used as a standalone fabric; it is often blended with other types of fibers. The mainstream spandex on the market is a polyether-type spandex produced by dry spinning from polytetrahydrofuran ether diol and diisocyanate. Conventional spandex is usually dyed with disperse or acid dyes; however, in practical use, spandex has poor dye uptake and color fastness. When blended with other fibers and dyed, color differences or "white showing" may occur, significantly affecting the appearance of textile products. The reason for this is that the molecular structure of spandex is mainly composed of a less polar polyether portion and a more polar polyurethane or polyurethane urea portion. The polyether portion of mainstream spandex products is a residue of polytetrahydrofuran ether diol, which belongs to the non-crystalline region in the microphase separation structure. Its loose structure provides elasticity to the spandex fiber and is the main site for disperse dyeing, but its binding force with disperse dyes is weak. The polyurethane or polyurethane urea portion can theoretically be dyed with acidic, neutral, and acidic mediums and disperse dyes through hydrogen bonds and their coordination bonds. However, since this part is a crystalline region with tightly packed molecular chain segments, it is difficult for dye molecules to diffuse into the interior of the crystalline region, resulting in a significant decrease in the dyeing rate.
[0003] To address the aforementioned issues, this invention provides an easily dyeable spandex fiber that improves the dyeing rate and color-fixing ability of spandex fibers for disperse and acid dyes. Summary of the Invention
[0004] A dyeable spandex, characterized in that the soft segments of the molecular structure of the dyeable spandex contain repeating units as described in formula (1):
[0005]
[0006] Wherein R1 is at least one of aromatic ring and aromatic heterocycle, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of straight-chain saturated alkane groups with 2 to 3 carbon atoms; x is 2 to 20;
[0007] The mass of the repeating unit shown in formula (1) accounts for more than 2% of the mass of the spandex soft segment, preferably more than 5%, more preferably more than 10%, less than 70%, and preferably less than 65%.
[0008] Optionally, the soft segments of the spandex molecular structure may also include polytetramethylene ether segments.
[0009] In this invention, the mass of the soft segment refers to the mass of the molecular structure of the portion of spandex made from diol raw materials after the reaction with diisocyanate, after the terminal hydroxyl groups have been removed. The diol raw materials refer to diol compounds used as soft segment raw materials for polyurethane, including polyether ester polyols as defined in this invention, and optionally polytetrahydrofuran ether diols, but excluding small molecule diol compounds used as chain extenders.
[0010] The high-resilience coarse denier spandex can be prepared by dry spinning or melt spinning. Specifically, the preparation method by dry spinning is as follows:
[0011] A method for preparing easily dyeable spandex, characterized by comprising the following steps:
[0012] Step 1): End-capping diol raw materials with diisocyanate raw materials to prepare prepolymers;
[0013] Step 2): Dissolve the prepolymer using a polar solvent to obtain a prepolymer solution;
[0014] Step 3): Chain extend the prepolymer using a mixed solution of chain extender and terminator to obtain a polyurethane / polyurethane urea solution;
[0015] Step 4): Add auxiliaries to prepare the spinning solution;
[0016] Step 5): The obtained spinning solution is used to produce easily dyeable spandex through spinning equipment.
[0017] The preparation method of melt spinning is as follows:
[0018] A method for preparing easily dyeable spandex includes the following steps:
[0019] Step a) Add the diisocyanate raw material, diol raw material, and small molecule polyol chain extender into the reaction vessel respectively;
[0020] Step b) Mix the materials in the reaction vessel, and heat the materials during or after mixing to react and then extrude and granulate them to obtain polyurethane particles;
[0021] Step c) Dry the polyurethane particles, add auxiliaries, and then perform melt spinning to obtain easily dyeable spandex.
[0022] In one embodiment of the present invention, the diol raw material includes a polyether ester polyol with an aromatic group-polyether block structure, wherein the polyether ester polyol is composed of repeating units and capped alcohol hydroxyl groups as shown in formula (1):
[0023]
[0024] Wherein R1 is at least one of aromatic ring and aromatic heterocyclic ring, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of direct-linked saturated alkane groups with 2 to 3 carbon atoms; x is 2 to 20; preferably 3 to 10; the average functionality of the terminal alcohol hydroxyl group is 1.95 to 2.00; the number average molecular weight of the polyether ester polyol is 800 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300.
[0025] Optionally, the polyether ester polyol is subjected to a temperature of 90°C and a shear rate of 1 s. -1 The viscosity can be less than 500 poise, preferably less than 200 poise.
[0026] Optionally, the polyether ester polyol has a mass ratio of more than 2% in the diol raw material, preferably more than 5%, and more preferably more than 10%.
[0027] Optionally, the polyether ester polyol has a mass ratio of less than 70% in the diol raw material, preferably less than 65%.
[0028] Optionally, the diol raw materials may also include other diol compounds that can be used as spandex soft segments, such as polytetrahydrofuran ether diol, polyethylene glycol, polypropylene glycol and other polyether diols, polybutylene adipate diol, adipic acid and mixed diols (such as ethylene glycol / 1,4-butanediol, ethylene glycol / 1,2-propanediol, 1,6-hexanediol / 2,2-dimethylpropanediol-1,3) copolyester diols, other polyether ester diols that can be used as spandex soft segments, or mixtures of at least two of the above diol compounds.
[0029] Preferably, the second type of diol raw material accounts for 30%-95% of all diol raw materials. That is, the preferred option is that the polyol is blended with the second type of diol raw material as the diol raw material for spandex.
[0030] The preferred second type of diol raw material is furan ether diol.
[0031] In another embodiment of the present invention, the diol raw material includes a polyether ester polyol with an aromatic group-polyether block structure, the polyether ester polyol comprising a repeating unit and a capped alcohol hydroxyl group as shown in formula (1):
[0032]
[0033] Wherein R1 is at least one of aromatic ring and aromatic heterocyclic ring, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of direct-linked saturated alkane groups with 2-3 carbon atoms; x is 2-20; preferably 3-10; the repeating unit shown in formula (1) has a mass percentage greater than 5% in the polyether ester polyol; the average functionality of the capped alcohol hydroxyl group is 1.95-2.00, and the number average molecular weight of the polyether ester polyol is 800-5000, preferably 1000-3500, more preferably 1400-2500, and most preferably 1500-2300.
[0034] The polyether ester polyol may contain some other polyester or polyether structures, or some aliphatic structures as modified structures.
[0035] Similarly, the aforementioned polyether ester polyols can be blended with the second type of diol raw materials described above as diol raw materials for spandex.
[0036] Beneficial effects:
[0037] The easily dyeable spandex provided by this invention involves adding a polyether ester polyol with a specific structure to a glycol-based raw material. This results in the spandex fiber having a specific aromatic group-polyether block structure in its molecular soft segments, thus producing easily dyeable spandex. Compared to conventional spandex, the easily dyeable spandex of this invention can increase the dyeing rate and colorfastness of spandex for disperse and acid dyes without compromising its mechanical properties.
[0038] By adjusting the mass ratio of the aromatic group-polyether block structure in the soft segments of the spandex molecule, the spandex can achieve good alkali resistance while maintaining sufficient dye uptake and fixation rates. Detailed Implementation
[0039] This invention provides an easily dyeable spandex that exhibits good dyeing rate and colorfastness to disperse and acid dyes. The soft segments of the molecular structure of the easily dyeable spandex comprise repeating units as shown in formula (1):
[0040]
[0041] Wherein R1 is at least one of aromatic ring and aromatic heterocycle, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of straight-chain saturated alkane groups with 2 to 3 carbon atoms; x is 2 to 20;
[0042] The mass of the repeating unit shown in Equation (1) accounts for more than 5% of the mass of the soft segment, preferably more than 10%.
[0043] Optionally, the soft segments of the spandex molecular structure may also include polytetramethylene ether segments.
[0044] For ease of description, aromatic rings or heterocyclic aromatic rings represented by R1 are collectively referred to as aromatic groups in this text.
[0045] Since both disperse dyeing and acid dyeing are carried out in an aqueous solution of the dye molecules, all dye molecules are dissolved in water. The diol raw material used in ordinary spandex yarn is polytetrahydrofuran, and the prepared polyurethane urea polymer is hydrophobic. The easily dyeable spandex provided by this invention has the structure of formula (1) above, wherein (R2-O) x This structure, which increases the hydrophilicity of the molecular chain, is introduced into the spandex molecular structure through polyether ester polyols prepared from PEG and P3OG (polyethylene glycol and poly1,3-propanediol, especially polyethylene glycol) and aromatic diacids. Compared to polytetrahydrofuran, this structure contains a higher density of ether-oxygen bonds. The polyurethane urea polymer prepared using this polyether ester polyol exhibits stronger hydrophilicity, making spandex more easily swollen by the dye bath during acid dyeing and disperse dyeing. The increased intermolecular spacing allows dye molecules to penetrate the spandex filament more easily. Furthermore, since acid dyes and disperse dyes are mostly macromolecules containing aromatic rings, the aromatic ring structure introduced by the polyether ester polyol has stronger van der Waals forces with the dye molecules. This results in stronger interactions between the dye molecules penetrating the spandex and the polyether ester polyol, making it easier for them to be fixed within the spandex molecule. Consequently, this leads to higher dye uptake and fixation rates for acid dyeing and disperse dyeing.
[0046] While meeting the requirements for dye uptake and fixation rate, the introduction of the structure of formula (1) should avoid affecting the mechanical properties of spandex as much as possible. Therefore, the present invention makes more specific requirements for the structure of formula (1).
[0047] In the repeating unit shown in formula (1), if the content of the aromatic group R1 is too high, it will cause the molecular rigidity of the final spandex to be too large, affecting the elongation at break and the ability to resist plastic deformation of the spandex; while if the content of the aromatic group R1 is too low, it will not play a role in reducing the permanent deformation rate of the spandex, and at the same time, it will lead to a decrease in the recovery modulus of the spandex. Therefore, in this invention, the mass content of R1 in the repeating unit is preferably 4.5% to 44%. Among them, R1 is at least one of aromatic ring and aromatic heterocyclic ring. The aromatic ring can be at least one of the aromatic rings such as benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, etc.; the aromatic heterocyclic ring can be at least one of the pyridine ring, furan ring, thiazole ring, pyrimidine ring, etc. In an optional embodiment, R1 includes 1-4 methylene groups in addition to the aromatic ring or aromatic heterocyclic ring.
[0048] In the structure of equation (1) above, (R2-O) xThe structure actually represents a polyether segment, where 'x' represents the degree of polymerization of the (R2-O) structure. The degree of polymerization 'x' of the polyether segment is preferably 2-20, more preferably 3-10. The molecular weight of the polyether segment can be 100-1000, preferably 300-1000, more preferably 600-900. In fact, only when the degree of polymerization and number-average molecular weight of the polyether segment are within the above ranges can the influence of the polyether ester structure on the mechanical properties of spandex be minimized. (R2-O) x If the polyether chain segment length is too short, the resulting spandex molecule will be too rigid, affecting the elongation at break of the spandex, while (R2-O) x Excessive chain length will negatively impact the permanent deformation rate of spandex. In the polyether chain segment, R2 is preferably a directly linked saturated alkane group with 2-3 carbon atoms. For this invention, the fewer carbon atoms in R2, the higher the density of ether-oxygen bonds, resulting in stronger water absorption of the spandex and facilitating the penetration of dye molecules into the spandex fiber, thus improving the dye uptake rate. Branched molecular structures, on the other hand, negatively affect the water absorption of spandex. Therefore, in this invention, R2 is preferably a directly linked saturated alkane group, specifically (R2-O). x It can be a polyether segment of PEG, a polyether segment of P3OG, or a polyether segment of ethylene glycol and 1,3-propanediol coether, with the most preferred being a straight-chain saturated alkane group having 2 carbon atoms.
[0049] In the spandex molecular structure described in this invention, the structure shown in formula (1) should occupy a certain proportion in the soft segment to improve the dye uptake and fixation rate of the spandex. In this invention, the mass percentage of the structure shown in formula (1) in the soft segment should be greater than 2%, preferably greater than 5%, more preferably greater than 10%, more preferably greater than 30%, and most preferably greater than 50%.
[0050] The polyether ester structure shown in formula (1) has a relatively small impact on the mechanical properties of spandex. Therefore, its mass proportion in the soft segment can be appropriately increased. However, due to the presence of ester groups in this structure, spandex containing this structure has a certain gap in alkali resistance compared to spandex made from polytetrahydrofuran ether diol. This may result in a loss of mechanical properties during the dyeing and finishing process. Therefore, the mass proportion of the polyether ester structure shown in formula (1) in the soft segment of spandex should not be too high, preferably less than 80%, more preferably less than 70%, and even more preferably less than 65%. Specifically, spandex prepared from polyether ester polyol can be blended with spandex prepared from polyether polyol in the form of raw materials, prepolymers, and polymers to improve the alkali resistance of spandex prepared from polyether ester polyol.
[0051] This invention also provides a method for preparing the above-mentioned easily dyeable spandex. The easily dyeable spandex can be prepared by dry spinning or melt spinning, wherein dry spinning includes the following steps:
[0052] Step 1): End-capping diol raw materials with diisocyanate raw materials to prepare prepolymers;
[0053] Step 2): Dissolve the prepolymer using a polar solvent to obtain a prepolymer solution;
[0054] Step 3): Chain extend the prepolymer using a mixed solution of chain extender and terminator to obtain a polyurethane / polyurethane urea solution;
[0055] Step 4): Add auxiliaries to prepare the spinning solution;
[0056] Step 5): The obtained spinning solution is used to produce easily dyeable spandex through spinning equipment.
[0057] Compared to conventional dry spinning of spandex, the improvement of the present invention mainly lies in the change of diol raw materials.
[0058] In one embodiment of the present invention, the diol raw material includes a polyether ester polyol with an aromatic group-polyether block structure, wherein the polyether ester polyol is composed of repeating units and capped alcohol hydroxyl groups as shown in formula (1):
[0059]
[0060] Wherein R1 is at least one of aromatic ring and aromatic heterocyclic ring, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of direct-linked saturated alkane groups with 2 to 3 carbon atoms; x is 2 to 20; preferably 3 to 10; the average functionality of the terminal alcohol hydroxyl group is 1.95 to 2.00; the number average molecular weight of the polyether ester polyol is 800 to 5000, preferably 1000 to 3500, more preferably 1400 to 2500, and most preferably 1500 to 2300.
[0061] Optionally, the polyether ester polyol is subjected to a temperature of 90°C and a shear rate of 1 s. -1 The viscosity can be less than 500 poise, preferably less than 200 poise.
[0062] The polyether ester polyol can be obtained by condensation or transesterification of an aromatic diacid, its esterified form, or its anhydride with a polyether glycol. In one embodiment, the esterified form can be obtained by reacting an aromatic diacid with a monohydric alcohol with a boiling point below 150°C, such as methanol, ethanol, n-butanol, or n-hexanol, which can then be easily removed by distillation in subsequent esterification or transesterification reactions; the small molecule alcohol is preferably methanol or ethanol. Moreover, compared to aromatic diacids, the transesterification reaction between the aforementioned esterified form and the polyether glycol can be carried out under milder reaction conditions, which is beneficial for production process design. The aromatic diacids suitable for this invention can be derived from recycled plastics, thereby achieving waste recycling and reducing the production cost of polyurethane fibers, which is more in line with the current requirements of a green economy.
[0063] To ensure that dye molecules can more easily penetrate the spandex filament, the polyether diol is preferably at least one of the following: a straight-chain saturated alkane group with 2-3 carbon atoms. A high density of ether-oxygen bonds gives the polyether segment stronger hydrophilicity, allowing the spandex to swell more easily in the dye bath during acid dyeing and disperse dyeing. This increases the intermolecular gaps, making it easier for dye molecules to penetrate the spandex filament. Specifically, the polyether diol can be polyethylene glycol (PEG), poly1,3-propanediol (P3OG), or a copolyether diol of ethylene glycol and 1,3-propanediol. Preferably, the polyether diol is polyethylene glycol (PEG), which has a higher ether-oxygen bond density, giving the spandex better hydrophilicity and thus making it easier for dye molecules to penetrate the spandex filament.
[0064] The aromatic dicarboxylic acid can be selected from one or more of terephthalic acid, isophthalic acid, phthalic acid, biphenyl dicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,5-furandicarboxylic acid, terephthalic acid, isophthalic acid, and phthalic acid. Since acid dye molecules and disperse dye molecules are mostly macromolecules containing aromatic rings, the aromatic ring structure introduced by polyether ester polyols has stronger van der Waals forces with dye molecules. This results in stronger interaction between dye molecules entering the spandex and polyether ester segments, making it easier for them to be fixed into the spandex molecules. Therefore, under the combined effect of polyether segments and aromatic ring structures, spandex with a polyether-aromatic ring structure has better dye uptake and fixation rates than conventional spandex.
[0065] Using the polyether ester polyol containing aromatic groups-polyether block structure as the soft segment raw material of spandex, the structure described in formula (1) can be introduced into the molecular structure of spandex.
[0066] To ensure that the polyether ester segments do not adversely affect the mechanical properties of spandex, the number average molecular weight of the polyether ester polyols mentioned above should be 800-5000, preferably 1000-3500, more preferably 1400-2500, and most preferably 1500-2300. The higher the number average molecular weight of the polyether ester polyol, the higher its viscosity, making continuous operation on an industrial scale difficult. However, if the molecular weight of the polyether ester polyol is too low, more diisocyanate is required in the synthesis when the molecular weight of the polyurethane prepolymer needs to be consistent, resulting in a higher content of urethane groups in the prepolymer. This strengthens the interaction between prepolymer molecules, increasing viscosity. Furthermore, the resulting polyurethane has a shorter soft segment length, which affects the recovery properties of the final polyurethane fiber.
[0067] In the polyether ester polyols described above, the average functionality of the terminal hydroxyl groups can be 1.95-2.00, preferably 1.96-2.00, and more preferably 1.98-2.00. This ensures that the polyether ester polyol can be smoothly terminalized with isocyanate and subsequently chain-extended by small molecule amines or alcohols. "Average functionality" represents the average number of moles of hydroxyl groups that can participate in the reaction per mole of polyether ester polyol. In this invention, considering the dehydration of terminal hydroxyl groups in polyether diols to form double bonds and the presence of unreacted carboxyl groups, the average functionality of the hydroxyl groups can be calculated using the following formula:
[0068] Functionality = 2 * number of moles of hydroxyl groups / (number of moles of hydroxyl groups + number of moles of carboxyl groups + number of moles of double bonds)
[0069] In the aforementioned polyether ester polyols, the presence of ester groups means that using only this polyether ester polyol as the diol raw material for spandex will result in a certain gap in alkali resistance compared to polyether-type spandex. Therefore, to limit the mass ratio of aromatic group-polyether block structures in the soft segments of spandex, a specific method to control the mass ratio is to blend spandex prepared from polyether ester polyols with spandex prepared from polyether-type polyols in the form of diol raw materials, prepolymers, or polymers to improve the alkali resistance of spandex prepared from polyether ester polyols.
[0070] Taking the blending of diol raw materials for spandex as an example, in order to make the spandex have better dyeing rate and color fixation rate, the mass ratio of the polyether ester polyol in the diol raw materials should be greater than 2%, preferably greater than 5%, preferably greater than 10%, more preferably greater than 20%, more preferably greater than 30%, more preferably greater than 40%, and most preferably greater than 50%.
[0071] To ensure the alkali resistance of the prepared spandex, the mass ratio of the polyether ester polyol in the diol raw materials is less than 80%, preferably less than 70%, and more preferably less than 65%.
[0072] Optionally, in addition to the polyether ester polyols mentioned above, the diol raw materials may also include other diol compounds that can serve as the soft segment of spandex, as the second type of diol raw materials, such as polytetrahydrofuran ether diol, polyethylene glycol, polypropylene glycol, etc., polybutylene adipate diol, adipic acid, and copolyester diols (such as ethylene glycol / 1,4-butanediol, ethylene glycol / 1,2-propanediol, 1,6-hexanediol / 2,2-dimethylpropanediol-1,3), as well as other polyether ester diols that can serve as the soft segment of spandex, or mixtures of at least two of the above diol compounds. To ensure the alkali resistance of spandex, polyether diols are preferred as the second type of diol raw materials, and polytetrahydrofuran ether diol is most preferred. Preferably, the second type of diol raw materials account for 30%-98% of the total diol raw materials, more preferably 35%-90%. That is, the preferred option is to blend the polyether ester polyol with the second type of diol raw material as the diol raw material for spandex.
[0073] The method of blending prepolymers or polymers is similar to that described above, and will not be repeated here.
[0074] To ensure the alkali resistance of the prepared spandex, in another embodiment of the present invention, the diol raw material includes a polyether ester polyol with an aromatic group-polyether block structure, wherein the polyether ester polyol comprises a repeating unit and a capped alcohol hydroxyl group as shown in formula (1):
[0075]
[0076] Wherein R1 is at least one of aromatic ring and aromatic heterocyclic ring, and the mass content of R1 in the repeating unit is 4.5% to 44%; R2 is at least one of direct-linked saturated alkane groups with 2-3 carbon atoms; x is 2-20; preferably 3-10; the repeating unit shown in formula (1) has a mass percentage greater than 2% in the polyether ester polyol, preferably greater than 5%, and more preferably greater than 10%; the average functionality of the capped alcohol hydroxyl group is 1.95-2.00, and the number average molecular weight of the polyether ester polyol is 800-5000, preferably 1000-3500, more preferably 1400-2500, and most preferably 1500-2300.
[0077] Unlike the previous embodiment which used a blending method of polyether ester polyol and type II diol raw materials, this embodiment chooses to reduce the proportion of the cyclic structure in formula (1) in the polyether ester polyol. Similarly, in order to balance the dyeing performance and alkali resistance of spandex, in the preferred embodiment, the mass ratio of the cyclic structure in formula (1) in the polyether ester polyol should be greater than 5%, preferably greater than 10%, more preferably greater than 30%, and most preferably greater than 50%. At the same time, it is preferred to be less than 80%, more preferably less than 70%, and more preferably less than 65%. The remaining part of the polyether ester polyol may contain some other polyester structures or polyether structures, or some aliphatic structures as modified structures. In order to ensure the mechanical properties of spandex, polyether structures are preferred, and polytetramethylene ether structures are most preferred.
[0078] Similarly, the aforementioned polyether ester polyols can be blended with the second type of diol raw materials described above as diol raw materials for spandex.
[0079] In the method for preparing easily dyeable spandex described in this invention, the diisocyanate raw material in step 1) can be one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and their isomers.
[0080] The polar solvent in step 2) is at least one of N,N-dimethylformamide or N,N-dimethylacetamide.
[0081] The chain extender in step 3) can be an amine or an alcohol chain extender. The amine chain extender can be a diamine with 2 to 30 carbon atoms, such as one or more of ethylenediamine, propylenediamine, butanediamine, pentanediamine, methylpentanediamine, methylpropylenediamine, hexanediamine, triethylenediamine, phenylenediamine, phenylenediamine, diaminocyclohexane, hexamethylenediamine, and dopamine. The alcohol chain extender can be one or more of common chain extenders such as ethylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexanediol, 1,3-propanediol, and 1,4-dihydroxymethylcyclohexane. The chain terminator can be a monoamine with 2 to 20 carbon atoms, and can be selected from one or more of ethylamine, isopropylamine, n-butylamine, tert-butylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, di-n-butylamine, di-tert-butylamine, diisobutylamine, diisopropylamine, cyclohexylamine, or ethanolamine.
[0082] Melt spinning includes the following steps:
[0083] Step a) Add the diisocyanate raw material, diol raw material, and small molecule polyol chain extender into the reaction vessel respectively;
[0084] Step b) Mix the materials in the reaction vessel, and heat the materials during or after mixing to react and then extrude and granulate them to obtain polyurethane particles;
[0085] Step c) Dry the polyurethane particles, add additives, and then perform melt spinning.
[0086] The raw materials for preparing spandex by melt spinning, such as diisocyanate and diol, are similar to those for dry spinning. The difference is that the chain extender in step a) is only an alcohol chain extender.
[0087] Example
[0088] The present invention will be described in more detail below through embodiments, wherein the specific testing methods for the parameters involved are as follows:
[0089] 1. Average functionality:
[0090] Functionality = 2 * number of moles of hydroxyl groups / (number of moles of hydroxyl groups + number of moles of carboxyl groups + number of moles of double bonds).
[0091] The acid value was determined using the method described in HG / T 2708-1995; the hydroxyl value was determined using the method described in HG / T 2709 / 1995; and the degree of unsaturation was determined using the method described in GB / T 12008.6-2010. The corresponding acid value, hydroxyl value, and degree of unsaturation were then converted into the molar number of the corresponding end groups in the polyether diol.
[0092] 2. Tensile stress at 300%, breaking strength and elongation at break: all in accordance with the "Test Method for Tensile Properties of Spandex Yarn" in the "Textile Industry Standard of the People's Republic of China" FZ / T 50006-2013.
[0093] 3. Dye uptake rate of acid dyes and color fixation rate after soaping:
[0094] In this invention, Acid Red is used as the acid dye. The dye concentration in the dye bath before dyeing is A, the dye concentration after dyeing is B, and the dye concentration in the washing solution after soaping is C. The results are as follows:
[0095] Acid dye uptake rate = (AB) / A
[0096] Fixation rate of acid dyes after soaping = (ABC) / A
[0097] 4. Dye uptake rate of disperse dyes and color fixation rate after soaping:
[0098] In this invention, disperse orange is used as the spinning dye. The dye concentration in the dye bath before dyeing is P, the dye concentration after dyeing is Q, and the dye concentration in the washing solution after soaping is M. The results are as follows:
[0099] Disperse dye uptake rate = (PQ) / P
[0100] Fixation rate of disperse dyes after soaping = (PQM) / P
[0101] 5. Hysteresis test of spandex yarn:
[0102] In this invention, the degree of fiber hysteresis is characterized by the ratio of the tensile stress at the fifth stretch to 200% to the recovery stress at the fifth recovery to 200% through a 5-cycle tensile test. A smaller ratio indicates more severe hysteresis in the spandex, while a larger ratio indicates less hysteresis. Specifically, in the following text, "5LP200%" represents the tensile stress value at the fifth stretch to 200% elongation, i.e., F1; "5UP200%" represents the rebound stress value at the fifth recovery to 200% elongation, i.e., F2; and "5UP200% / 5LP 200%" represents the ratio of the recovery stress at the fifth recovery to 200% to the tensile stress at the fifth stretch to 200% in the 5-cycle tensile test.
[0103] 6. Alkali resistance test of spandex yarn:
[0104] Spandex yarn was boiled in a 10 g / L potassium hydroxide solution at 100°C for 1 hour to test its mechanical properties before and after boiling.
[0105] In addition, the antioxidant mentioned in the following examples is antioxidant 245, the dyeing auxiliary is DH300R or 2462B, and the light stabilizer is Tinuvin 791, all of which are commercially available.
[0106] Example 1
[0107] 17 parts by weight of polyethylene glycol PEG600 (number average molecular weight 600) and 2.7 parts by weight of terephthalic acid were added to a reactor, and nitrogen gas was introduced to replace the air in the reactor. The stirrer in the reactor was turned on at a speed of 150 rpm. The system was programmed to heat to 150°C and held for 5 hours; then the temperature was increased to 230°C and held until the water content reached more than 90% of the theoretical value, and the solution became homogeneous. Tetraisopropyl titanate catalyst was added, and the system was gradually evacuated to 2000 Pa. Once the acid value was below 0.5 mg KOH / g, a polyether ester glycol with a number average molecular weight of 1500 was obtained. The average functionality was tested to be 1.98, and the 1-second time at 90°C was measured. -1 The viscosity is 25 poise, and it is a liquid at room temperature.
[0108] Example 2
[0109] The polyether ester diol of Example 1 was used to prepare polyurethane elastic fibers.
[0110] 100 kg of the polyether ester polyol prepared in Example 1 was added to a reaction vessel that had been kept at a constant temperature of 45°C. Stirring was started at a speed of 150 rpm. 31 kg of diphenylmethane diisocyanate was added and stirred for 5 min. The mixture was then heated to 90°C and reacted at 90°C for 2 h to obtain the prepolymer.
[0111] The prepolymer was cooled to 50°C and dissolved using 166.72 kg of dimethylacetamide (DMAc). Then, an amine solution containing 2.40 kg of ethylenediamine and 0.29 kg of diethylamine (3.2% by mass) was added, and the stirring speed was increased to 300 rpm to initiate a chain extension reaction. After the chain extension reaction was completed, necessary antioxidants, dyeing auxiliaries, and other auxiliaries were added, and the mixture was allowed to mature for 30 hours to obtain a spinning solution with a solid content of 35%. The above solution was then dry-spun to obtain polyurethane elastic fiber PUU-1 with a denier of 40D.
[0112] Example 3
[0113] The polyether ester polyol and polytetrahydrofuran (PTMG) with a number average molecular weight of 2000 in Example 1 were used to prepare polyurethane fibers.
[0114] 50 kg of the polyether ester polyol prepared in Example 1 and 50 kg of polytetrahydrofuran with a number average molecular weight of 2000 were added to a reactor that had been kept at a constant temperature of 45°C. Stirring was started at 150 rpm, and 21.88 kg of diphenylmethane diisocyanate was added. After stirring for 5 min, the temperature was raised to 90°C. The reactor was then reacted at 90°C for 2 h to obtain the prepolymer.
[0115] The prepolymer was cooled to 50°C and dissolved using 161.3 kg of dimethylacetamide (DMAc). Then, an amine solution containing 2.38 kg of ethylenediamine and 0.29 kg of diethylamine (3.26% by mass) was added, and the stirring speed was increased to 300 rpm to initiate a chain extension reaction. After the chain extension reaction was completed, necessary antioxidants, dyeing auxiliaries, etc., were added (dyeing auxiliaries added at 1%, 2462B), and the mixture was allowed to mature for 30 hours to obtain a spinning solution with a solid content of 35%. The above solution was then dry-spun to obtain polyurethane elastic fiber PUU-2 with a denier of 40D.
[0116] Example 4
[0117] The prepolymer prepared from the polyether ester polyol of Example 1 and polytetrahydrofuran (PTMG) with a number average molecular weight of 2000 was used to prepare polyurethane fibers.
[0118] 50 kg of the polyether ester polyol prepared in Example 1 was added to a reactor that had been kept at a constant temperature of 45°C. Stirring was started at 150 rpm. 15.64 kg of diphenylmethane diisocyanate was added and stirred for 5 min. The mixture was then heated to 90°C and reacted at 90°C for 2 h to obtain prepolymer 1.
[0119] 50 kg of polytetrahydrofuran with a number average molecular weight of 2000 was added to a reactor that had been kept at a constant temperature of 45°C. Stirring was started at 150 rpm, and 11.1 kg of diphenylmethane diisocyanate was added. After stirring for 5 min, the temperature was raised to 90°C. The reactor was then allowed to react at 90°C for 2 h to obtain prepolymer 2.
[0120] Prepolymer 1 and prepolymer 2 were cooled to 50°C and transferred to the same reactor. The prepolymers were dissolved using 161.3 kg of dimethylacetamide (DMAc), followed by the addition of an amine solution containing 2.38 kg of ethylenediamine and 0.29 kg of diethylamine (3.26% by mass). The stirring speed was increased to 300 rpm to initiate a chain extension reaction. After the chain extension reaction was completed, necessary antioxidants, dyeing auxiliaries, etc., were added (dyeing auxiliaries added at 1%, 2462B), and the mixture was matured for 30 hours to obtain a spinning solution with a solid content of 35%. This solution was then dry-spun to obtain polyurethane elastic fiber PUU-3 with a denier of 40D.
[0121] Example 5
[0122] A stock solution prepared by blending 100 kg of the stock solution obtained in Example 2 and 100 kg of the stock solution obtained in Comparative Example 1 was used to prepare polyurethane fibers.
[0123] Take 100 kg of the stock solution PUU3 prepared in Example 8 and 100 kg of the stock solution PUU0 prepared in Comparative Example 1, mix them evenly using a combination of stirring and static mixing in a reactor, and then dry spin the above stock solution to obtain polyurethane elastic fiber PUU-4 with a denier of 40D.
[0124] Example 6
[0125] The polyether ester polyol and polytetrahydrofuran (PTMG) with a number average molecular weight of 2000 in Example 1 were used to prepare polyurethane fibers.
[0126] 10 kg of the polyether ester polyol prepared in Example 1 and 90 kg of polytetrahydrofuran with a number average molecular weight of 2000 were added to a reactor that had been kept at a constant temperature of 45°C. Stirring was started at 150 rpm, and 21.88 kg of diphenylmethane diisocyanate was added. After stirring for 5 min, the temperature was raised to 90°C. The reactor was then reacted at 90°C for 2 h to obtain the prepolymer.
[0127] The prepolymer was cooled to 50°C and dissolved using 161.3 kg of dimethylacetamide (DMAc). Then, an amine solution containing 2.38 kg of ethylenediamine and 0.29 kg of diethylamine (3.26% by mass) was added, and the stirring speed was increased to 300 rpm to initiate a chain extension reaction. After the chain extension reaction was completed, necessary antioxidants, dyeing auxiliaries, etc., were added (dyeing auxiliaries added at 1%, 2462B), and the mixture was matured for 30 hours to obtain a spinning solution with a solid content of 35%. The above solution was then dry-spun to obtain polyurethane elastic fiber PUU-5 with a denier of 40D.
[0128] Example 7
[0129] The polyether ester polyol and polytetrahydrofuran (PTMG) with a number average molecular weight of 2000 in Example 1 were used to prepare polyurethane fibers.
[0130] 65 kg of the polyether ester polyol prepared in Example 1 and 35 kg of polytetrahydrofuran with a number average molecular weight of 2000 were added to a reactor that had been kept at a constant temperature of 45°C. Stirring was started at 150 rpm, and 21.88 kg of diphenylmethane diisocyanate was added. After stirring for 5 min, the temperature was raised to 90°C. The reactor was then reacted at 90°C for 2 h to obtain the prepolymer.
[0131] The prepolymer was cooled to 50°C and dissolved using 161.3 kg of dimethylacetamide (DMAc). Then, an amine solution containing 2.38 kg of ethylenediamine and 0.29 kg of diethylamine (3.26% by mass) was added, and the stirring speed was increased to 300 rpm to initiate a chain extension reaction. After the chain extension reaction was completed, necessary antioxidants, dyeing auxiliaries, etc., were added (dyeing auxiliaries added at 1%, 2462B), and the mixture was allowed to mature for 30 hours to obtain a spinning solution with a solid content of 35%. The above solution was then dry-spun to obtain polyurethane elastic fiber PUU-6 with a denier of 40D.
[0132] Comparative Example 1
[0133] Polytetrahydrofuran (PTMG) stock solution with a number average molecular weight of 2000 was used to prepare polyurethane elastic fibers.
[0134] 100 kg of polytetrahydrofuran (PTMG2000) (number average molecular weight 2000) was added to a reactor that had been kept at a constant temperature of 45°C. Stirring was started at 150 rpm. 22.2 kg of diphenylmethane diisocyanate was added, and after stirring for 5 min, the temperature was raised to 90°C. The mixture was reacted at 90°C for 2 h to obtain the prepolymer.
[0135] The prepolymer was cooled to 50°C and dissolved using 155.5 kg of dimethylacetamide (DMAc). Then, a 3.2% amine solution containing 2.26 kg of ethylenediamine and 0.28 kg of diethylamine was added, and the stirring speed was increased to 300 rpm to initiate a chain extension reaction. After the chain extension reaction was complete, necessary antioxidants, dyeing auxiliaries, and other auxiliaries were added, and the mixture was allowed to mature for 30 hours to obtain a spinning solution with a solid content of 35%. The above solution was then dry-spun to obtain polyurethane elastic fiber PUU-0 with a denier of 40D.
[0136] Following the testing methods described above, the mechanical property test results of the polyurethane elastic fibers (i.e., spandex filaments) obtained in the above embodiments and comparative examples are summarized in the table below:
[0137] Table 1 Comparison of Mechanical Performance Tests
[0138]
[0139] As can be seen from the table above, the spandex yarn obtained by the method of the present invention does not show a significant decrease in mechanical properties compared with conventional polyether spandex.
[0140] Following the test methods described above, the dyeing performance test results of the polyurethane elastic fibers (i.e., spandex filaments) obtained in the above examples and comparative examples are summarized in the table below:
[0141] Table 2 Comparison of dyeing performance of acid dyes
[0142] Acid dye dyeing Dyed yarn weight, g Dyeing rate, % Color fixation rate after soaping, % PUU-0 1.32 10.68 5.63 PUU-1 1.33 62.45 41.35 PUU-2 1.31 31.25 23.25 PUU-3 1.32 32.23 22.13 PUU-4 1.33 29.25 20.16 PUU-5 1.33 15.61 9.30 PUU-6 1.34 43.50 30.21
[0143] Table 3 Comparison of dyeing performance of disperse dyes
[0144] Acid dye dyeing Dyed yarn quality, g Dyeing rate, % Color fixation rate after soaping, % PUU-0 1.51 15.2 7.65 PUU-1 1.53 56.48 42.65 PUU-2 1.55 31.25 24.12 PUU-3 1.54 33.13 23.15 PUU-4 1.52 28.15 22.16 PUU-5 1.51 20.03 11.94 PUU-6 1.49 42.87 29.87
[0145] As shown in the table above, the spandex yarn prepared by the method of the present invention has significantly improved dyeing rate and fixation rate of both acid dyes and disperse dyes compared with conventional polyether spandex.
[0146] Following the test methods described above, the alkali resistance test results of the polyurethane elastic fibers (i.e., spandex filaments) obtained in the above examples and comparative examples are summarized in the table below:
[0147] Table 4 Comparison of Alkali Resistance Test Results
[0148]
[0149]
[0150] As shown in the table above, after boiling in alkaline solution, the mechanical properties of PUU-1, which is made entirely of polyether ester polyol as the soft segment raw material, deteriorated to some extent, while the mechanical properties of PUU-2 to PUU-6, which are made of mixed soft segment raw materials, changed less than before boiling in alkaline solution.
[0151] The test results above show that the easily dyeable spandex provided by this invention, compared with conventional spandex, significantly improves the dyeing rate and fixation rate of spandex yarn for acid dyes and disperse dyes while ensuring mechanical properties. By adjusting the formula, the problem of deterioration in the alkali resistance of spandex yarn is also avoided, thus meeting the requirements for mechanical properties, dyeability, and alkali resistance of spandex yarn.
Claims
1. A dyeable spandex characterized in that, The soft segments of the molecular structure of the easily dyeable spandex contain repeating units as shown in formula (1): Equation (1), Wherein R1 is at least one of aromatic ring and aromatic heterocycle, and the mass content of R1 in the repeating unit is 4.5%-44%; R2 is at least one of direct-linked saturated alkane groups with 2-3 carbon atoms; x is 2-20; The mass of the repeating unit shown in Equation (1) accounts for more than 2% and less than 70% of the mass of the spandex soft segment.
2. The easily dyeable spandex according to claim 1, characterized in that, The soft segments of the spandex molecular structure also include polytetramethylene ether segments.
3. A method for preparing easily dyeable spandex, characterized in that, Includes the following steps: Step 1): End-capping diol raw materials with diisocyanate raw materials to prepare prepolymers; Step 2): Dissolve the prepolymer using a polar solvent to obtain a prepolymer solution; Step 3): The prepolymer is chain extended using a mixed solution of chain extender and terminator to obtain a polyurethane / polyurethane urea solution; Step 4): Add auxiliaries to prepare the spinning solution; Step 5): The obtained spinning solution is used to produce easily dyeable spandex through spinning equipment; The diol raw materials include polyether ester polyols with aromatic group-polyether block structures, wherein the polyether ester polyols are composed of repeating units and capped alcohol hydroxyl groups as shown in formula (1): Equation (1), Wherein R1 is at least one of aromatic ring and aromatic heterocycle, and the mass content of R1 in the repeating unit is 4.5%-44%; R2 is at least one of direct-linked saturated alkane groups with 2-3 carbon atoms; x is 2-20; the average functionality of the capped alcohol hydroxyl group is 1.95-2.00; and the number average molecular weight of the polyether ester polyol is 800-5000. The polyether ester polyol has a mass ratio of greater than 5% and less than 70% in the diol raw materials.
4. The method for preparing easily dyeable spandex according to claim 3, characterized in that, Diol raw materials also include one or more of the following: polytetrahydrofuran ether diol, polyethylene glycol, polypropylene glycol, polybutylene adipate diol, adipic acid, and copolyester diols of mixed diols.
5. A method for preparing easily dyeable spandex, characterized in that, Includes the following steps: Step 1): End-capping diol raw materials with diisocyanate raw materials to prepare prepolymers; Step 2): Dissolve the prepolymer using a polar solvent to obtain a prepolymer solution; Step 3): The prepolymer is chain extended using a mixed solution of chain extender and terminator to obtain a polyurethane / polyurethane urea solution; Step 4): Add auxiliaries to prepare the spinning solution; Step 5): The obtained spinning solution is used to produce easily dyeable spandex through spinning equipment; The diol raw materials include polyether ester polyols with aromatic group-polyether block structures, wherein the polyether ester polyols contain repeating units and capped alcohol hydroxyl groups as shown in formula (1): Equation (1), Wherein R1 is at least one of aromatic ring and aromatic heterocyclic ring, and the mass content of R1 in the repeating unit is 4.5%-44%; R2 is at least one of direct-linked saturated alkane groups with 2-3 carbon atoms; x is 2-20; the repeating unit shown in formula (1) has a mass percentage greater than 5% and less than 70% in the polyether ester polyol; the average functionality of the capped alcohol hydroxyl group is 1.95-2.00, and the number average molecular weight of the polyether ester polyol is 800-5000.
6. A method for preparing easily dyeable spandex, characterized in that, Includes the following steps: Step a) Add the diisocyanate raw material, diol raw material, and small molecule polyol chain extender into the reaction vessel respectively; Step b) Mix the materials in the reaction vessel, and heat the materials during or after mixing to react and then extrude and granulate them to obtain polyurethane particles; Step c) Dry the polyurethane particles, add auxiliaries, and then perform melt spinning to obtain easily dyeable spandex; The diol raw materials include polyether ester polyols with aromatic group-polyether block structures, wherein the polyether ester polyols are composed of repeating units and capped alcohol hydroxyl groups as shown in formula (1): Equation (1), Wherein R1 is at least one of aromatic ring and aromatic heterocycle, and the mass content of R1 in the repeating unit is 4.5%-44%; R2 is at least one of direct-linked saturated alkane groups with 2-3 carbon atoms; x is 2-20; the average functionality of the capped alcohol hydroxyl group is 1.95-2.00; and the number average molecular weight of the polyether ester polyol is 800-5000. The polyether ester polyol has a mass ratio of greater than 5% and less than 70% in the diol raw materials.
7. A method for preparing easily dyeable spandex, characterized in that, Includes the following steps: Step a) Add the diisocyanate raw material, diol raw material, and small molecule polyol chain extender into the reaction vessel respectively; Step b) Mix the materials in the reaction vessel, and heat the materials during or after mixing to react and then extrude and granulate them to obtain polyurethane particles; Step c) Dry the polyurethane particles, add auxiliaries, and then perform melt spinning to obtain easily dyeable spandex; The diol raw materials include polyether ester polyols with aromatic group-polyether block structures, wherein the polyether ester polyols with aromatic group-polyether block structures are present in the following manner: The polyether ester polyol comprises the repeating unit shown in formula (1) and the capped alcohol hydroxyl group: Equation (1), Wherein R1 is at least one of aromatic ring and aromatic heterocyclic ring, and the mass content of R1 in the repeating unit is 4.5%-44%; R2 is at least one of direct-linked saturated alkane groups with 2-3 carbon atoms; x is 2-20; the repeating unit shown in formula (1) has a mass percentage greater than 5% and less than 70% in the polyether ester polyol; the average functionality of the capped alcohol hydroxyl group is 1.95-2.00, and the number average molecular weight of the polyether ester polyol is 800-5000.